Semiconductor device with diffusion barrier in the active contact

ABSTRACT

A semiconductor device including a substrate including an active pattern; a gate electrode crossing the active pattern and extending in a first direction; a source/drain pattern on the active pattern and adjacent to a side of the gate electrode; and an active contact in a contact hole on the source/drain pattern, wherein the active contact includes a first contact in a lower region of the contact hole, the first contact including a barrier pattern and a conductive pattern; a diffusion barrier layer on the first contact; and a second contact on the diffusion barrier layer, and a top surface of the diffusion barrier layer is coplanar with a top surface of the barrier pattern of the first contact.

CROSS-REFERENCE TO RELATED APPLICATION

Korean Patent Application No. 10-2019-0141059, filed on Nov. 6, 2019, inthe Korean Intellectual Property Office, and entitled: “SemiconductorDevice,” is incorporated by reference herein in its entirety.

BACKGROUND 1. Field

Embodiments relate to a semiconductor device.

2. Description of the Related Art

Due to their small-sized, multifunctional, and/or low-costcharacteristics, semiconductor devices are being esteemed as importantelements in the electronic industry. The semiconductor devices mayinclude a semiconductor memory device for storing data, a semiconductorlogic device for processing data, or a hybrid semiconductor deviceincluding both of memory and logic elements. As the electronic industryadvances, there is an increasing demand for semiconductor devices withimproved characteristics. For example, semiconductor devices with highreliability, high performance, and/or multiple functions may bedesirable. To achieve these characteristics, complexity and/orintegration density of semiconductor devices may be increased.

SUMMARY

The embodiments may be realized by providing a semiconductor deviceincluding a substrate including an active pattern; a gate electrodecrossing the active pattern and extending in a first direction; asource/drain pattern on the active pattern and adjacent to a side of thegate electrode; and an active contact in a contact hole on thesource/drain pattern, wherein the active contact includes a firstcontact in a lower region of the contact hole, the first contactincluding a barrier pattern and a conductive pattern; a diffusionbarrier layer on the first contact; and a second contact on thediffusion barrier layer, and a top surface of the diffusion barrierlayer is coplanar with a top surface of the barrier pattern of the firstcontact.

The embodiments may be realized by providing a semiconductor deviceincluding a substrate including an active pattern; a gate electrodecrossing the active pattern and extending in a first direction; asource/drain pattern on the active pattern and adjacent to a side of thegate electrode; and an active contact in a contact hole on thesource/drain pattern, wherein the active contact includes a firstcontact in a lower region of the contact hole, the first contactincluding a barrier pattern and a conductive pattern; a diffusionbarrier layer on the first contact; and a second contact on thediffusion barrier layer, and an outer side surface of the diffusionbarrier layer is in contact with an inner side surface of the barrierpattern of the first contact.

The embodiments may be realized by providing a semiconductor deviceincluding a substrate including a first active region and a secondactive region, which are spaced apart from each other in a firstdirection; a first active pattern on the first active region and asecond active pattern on the second active region, the first activepattern and the second active pattern extending in a second directioncrossing the first direction; a first source/drain pattern on an upperportion of the first active pattern and a second source/drain pattern onan upper portion of the second active pattern; gate electrodes crossingthe first active pattern and the second active pattern and extending inthe first direction, the gate electrodes being arranged in the seconddirection; an interlayered insulating layer covering the firstsource/drain pattern, the second source/drain pattern, and the gateelectrodes; and an active contact in a contact hole on one of the firstsource/drain pattern and the second source/drain pattern, wherein theactive contact includes a first contact in a lower region of the contacthole, the first contact including a first barrier pattern and a firstconductive pattern; a diffusion barrier layer on the first contact; anda second contact on the diffusion barrier layer, a top surface of thefirst conductive pattern is recessed, such that a recess region isdefined at an upper portion of the first contact by the top surface ofthe first conductive pattern and an inner side surface of the firstbarrier pattern, and the diffusion barrier layer is in the recessregion.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will be apparent to those of skill in the art by describing indetail exemplary embodiments with reference to the attached drawings inwhich:

FIG. 1 illustrates a plan view of a semiconductor device according to anembodiment.

FIGS. 2A to 2D illustrate sectional views, which are respectively takenalong lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1.

FIGS. 3, 5, 7, 9, and 11 illustrate plan views of stages in a method offabricating a semiconductor device, according to an embodiment.

FIGS. 4, 6A, 8A, 10A, and 12A illustrate sectional views taken alonglines A-A′ of FIGS. 3, 5, 7, 9, and 11, respectively.

FIGS. 6B, 8B, 10B, and 12B illustrate sectional views taken along linesB-B′ of FIGS. 5, 7, 9, and 11, respectively.

FIGS. 6C, 8C, 10C, and 12C illustrate sectional views taken along linesC-C′ of FIGS. 5, 7, 9, and 11, respectively.

FIGS. 10D and 12D illustrate sectional views taken along lines D-D′ ofFIGS. 9 and 11, respectively.

FIGS. 13 and 14 illustrate sectional views of an active contactaccording to an embodiment and in detail illustrating a region ‘M’ ofFIG. 2A and a portion ‘N’ of FIG. 2C.

FIGS. 15A to 15D illustrate sectional views, which are respectivelytaken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1.

FIG. 16 illustrates a sectional view of a semiconductor device accordingto an embodiment.

DETAILED DESCRIPTION

FIG. 1 is a plan view of a semiconductor device according to anembodiment. FIGS. 2A to 2D are sectional views, which are respectivelytaken along lines A-A′, B-B′, C-C′, and D-D′ of FIG. 1.

Referring to FIGS. 1 and 2A to 2D, a substrate 100 may include a firstactive region PR and a second active region NR. In an implementation,the first active region PR may be a PMOSFET region, and the secondactive region NR may be an NMOSFET region. The substrate 100 may be asemiconductor substrate, which is formed of or includes silicon,germanium, silicon-germanium, or the like, or a compound semiconductorsubstrate. In an implementation, the substrate 100 may be a siliconwafer.

In an implementation, the first and second active regions PR and NR maybe logic cell regions, on which logic transistors constituting a logiccircuit of the semiconductor device are disposed. In an implementation,logic transistors constituting a processor core or an I/O terminal maybe on the logic cell region of the substrate 100. The first activeregion PR and the second active region NR may include some portions(e.g., source/drain electrodes) of the logic transistors.

The first and second active regions PR and NR may be defined by a secondtrench TR2, which is in an upper portion of the substrate 100. Thesecond trench TR2 may be between the first and second active regions PRand NR. The first and second active regions PR and NR may be spacedapart from each other, in a first direction D1, with the second trenchTR2 therebetween. Each of the first and second active regions PR and NRmay extend (e.g., lengthwise) in a second direction D2 that is differentfrom the first direction D1.

First active patterns AP1 and second active patterns AP2 may be on thefirst active region PR and the second active region NR, respectively.The first and second active patterns AP1 and AP2 may extend in thesecond direction D2 to be parallel to each other. The first and secondactive patterns AP1 and AP2 may be vertically protruding (e.g., in avertical third direction D3) portions of the substrate 100. A firsttrench TR1 may be between adjacent ones of the first active patterns AP1and between adjacent ones of the second active patterns AP2. The firsttrench TR1 may be shallower than the second trench TR2 (e.g., asmeasured in the third direction D3).

A device isolation layer ST may fill the first and second trenches TR1and TR2. The device isolation layer ST may be formed of or include aninsulating material (e.g., silicon oxide). Upper portions of the firstand second active patterns AP1 and AP2 may protrude vertically above thedevice isolation layer ST. Each of the upper portions of the first andsecond active patterns AP1 and AP2 may be shaped like a fin. The deviceisolation layer ST may not cover the upper portions of the first andsecond active patterns AP1 and AP2. The device isolation layer ST maycover lower side surfaces of the first and second active patterns AP1and AP2.

First source/drain patterns SD1 may be on the upper portions of thefirst active patterns AP1. The first source/drain patterns SD1 may beimpurity regions of a first conductivity type (e.g., p-type). A firstchannel pattern CH1 may be between a pair of the first source/drainpatterns SD1. Second source/drain patterns SD2 may be on the upperportions of the second active patterns AP2. The second source/drainpatterns SD2 may be impurity regions of a second conductivity type(e.g., n-type). A second channel pattern CH2 may be between a pair ofthe second source/drain patterns SD2.

The first and second source/drain patterns SD1 and SD2 may be epitaxialpatterns, which are formed by a selective epitaxial growth process. Inan implementation, the first and second source/drain patterns SD1 andSD2 may have top surfaces (e.g., surfaces that face away from thesubstrate 100 in the third direction D3) that are coplanar with topsurfaces of the first and second channel patterns CH1 and CH2. In animplementation, the top surfaces of the first and second source/drainpatterns SD1 and SD2 may be higher than the top surfaces of the firstand second channel patterns CH1 and CH2 (e.g., as measured in the thirddirection D3). In an implementation, the top surface of the firstsource/drain pattern SD1 or the second source/drain pattern SD2 may belower than (or at a same level as) the top surface of the first channelpattern CH1 or the second channel pattern CH1 and CH2.

The first source/drain patterns SD1 may include a semiconductor element(e.g., SiGe) whose lattice constant is larger than a lattice constant ofa semiconductor element in the substrate 100. Accordingly, the firstsource/drain patterns SD1 may exert a compressive stress on the firstchannel patterns CH1. In an implementation, the second source/drainpatterns SD2 may include the semiconductor element (e.g., Si) as thesubstrate 100.

Gate electrodes GE may cross the first and second active patterns AP1and AP2 and may extend (e.g., lengthwise) in the first direction D1. Thegate electrodes GE may be spaced apart from each other in the seconddirection D2. The gate electrodes GE may be overlapped with the firstand second channel patterns CH1 and CH2, when viewed in a plan view.

The gate electrode GE may include a first metal pattern and a secondmetal pattern on the first metal pattern. The first metal pattern may beon a gate dielectric pattern GI and adjacent to the first and secondchannel patterns CH1 and CH2. The first metal pattern may include a workfunction metal, which may be used to adjust a threshold voltage of thetransistor. By adjusting a thickness and composition of the first metalpattern, it is possible to realize a transistor having a desiredthreshold voltage.

The first metal pattern may include a metal nitride. In animplementation, the first metal pattern may include, e.g., titanium(Ti), tantalum (Ta), aluminum (Al), tungsten (W), or molybdenum (Mo). Asused herein, the term “or” is not an exclusive term, e.g., “A or B”would include A, B, or A and B. In an implementation, the first metalpattern may include, e.g., nitrogen (N). In an implementation, the firstmetal pattern may include, e.g., carbon (C). The first metal pattern mayinclude a plurality of work function metal layers, which are stacked onthe substrate 100.

The second metal pattern may include a metallic material whoseresistance is lower than the first metal pattern. In an implementation,the second metal pattern may include, e.g., tungsten (W), aluminum (Al),titanium (Ti), or tantalum (Ta).

A pair of gate spacers GS may be on both side surfaces of each of thegate electrodes GE. The gate spacers GS may extend along the gateelectrodes GE and in the first direction D1. Top surfaces of the gatespacers GS may be higher (e.g., farther from the substrate 100 in thethird direction D3) than top surfaces of the gate electrodes GE. The topsurfaces of the gate spacers GS may be coplanar with a top surface of afirst interlayered insulating layer 110, which will be described below.The gate spacers GS may be formed of or include, e.g., SiCN, SiCON, orSiN. In an implementation, the gate spacers GS may have a multi-layeredstructure, which includes at least two different materials selected fromSiCN, SiCON, and SiN.

A gate capping pattern GP may be on each of the gate electrodes GE. Thegate capping pattern GP may extend along the gate electrode GE and inthe first direction D1. The gate capping pattern GP may be formed of orinclude a material that has an etch selectivity with respect to firstand second interlayered insulating layers 110 and 120 to be describedbelow. In an implementation, the gate capping patterns GP may be formedof or include, e.g., SiON, SiCN, SiCON, or SiN.

The gate dielectric pattern GI may be between the gate electrode GE andthe first active pattern AP1 and between the gate electrode GE and thesecond active pattern AP2. The gate dielectric pattern GI may extendalong a bottom (e.g., substrate 100-facing) surface of the gateelectrode GE thereon. In an implementation, the gate dielectric patternGI may cover a first top surface TS1 and opposing first side surfacesSW1 of the first channel pattern CH1. The gate dielectric pattern GI maycover a second top surface TS2 and opposing second side surfaces SW2 ofthe second channel pattern CH2. The gate dielectric pattern GI may covera top surface of the device isolation layer ST below the gate electrodeGE (e.g., see FIG. 2D).

In an implementation, the gate dielectric pattern GI may be formed of orinclude a high-k dielectric material, whose dielectric constant ishigher than that of silicon oxide. In an implementation, the high-kdielectric material may include, e.g., hafnium oxide, hafnium siliconoxide, hafnium zirconium oxide, hafnium tantalum oxide, lanthanum oxide,zirconium oxide, zirconium silicon oxide, tantalum oxide, titaniumoxide, barium strontium titanium oxide, barium titanium oxide, strontiumtitanium oxide, lithium oxide, aluminum oxide, lead scandium tantalumoxide, or lead zinc niobate.

The first interlayered insulating layer 110 may be on the substrate 100.The first interlayered insulating layer 110 may cover the gate spacersGS and the first and second source/drain patterns SD1 and SD2. A topsurface of the first interlayered insulating layer 110 may besubstantially coplanar with top surfaces of the gate capping patterns GPand the top surfaces of the gate spacers GS. A second interlayeredinsulating layer 120 may be on the first interlayered insulating layer110 to cover the gate capping patterns GP. A third interlayeredinsulating layer 130 may be on the second interlayered insulating layer120. The first to third interlayered insulating layers 110, 120, and 130may be formed of or include silicon oxide.

A pair of isolation structures, which may be opposite to each other inthe second direction D2, may be provided at both sides of a logic cell.The logic cell may include the first and second active regions PR andNR. The isolation structure may extend in the first direction D1 andparallel to the gate electrodes GE.

The isolation structure may penetrate the first and second interlayeredinsulating layers 110 and 120 and may extend in the first and secondactive patterns AP1 and AP2. The isolation structure may penetrate anupper portion of each of the first and second active patterns AP1 andAP2. The isolation structure may separate the first and second activeregions PR and NR of the logic cell from an active region of aneighboring logic cell.

Active contacts AC may penetrate the first and second interlayeredinsulating layers 110 and 120 and may be electrically connected to thefirst and second source/drain patterns SD1 and SD2. In animplementation, a contact hole CNH may penetrate the first and secondinterlayered insulating layers 110 and 120 and expose the first orsecond source/drain pattern SD1 and SD2 (e.g., see FIGS. 12A to 12C).The active contact AC may be in the contact hole CNH. The active contactAC may be between a pair of the gate electrodes GE. A lower region ofthe contact hole CNH (e.g., proximate to the substrate 100 in the thirddirection D3) may be in the first interlayered insulating layer 110 andmay have a first width in the first direction D1 or the second directionD2 and an upper region of the contact hole CNH (e.g., distal to thesubstrate 100 in the third direction D3) may be in the secondinterlayered insulating layer 120 and may have a second width in thefirst direction D1 or the second direction D2, the second width beingless than the first width (see, e.g., FIG. 16).

Each of the active contacts AC may include a first contact CT1, adiffusion barrier layer INH on the first contact CT1, and a secondcontact CT2 on the diffusion barrier layer INH.

The first contact CT1 may be in a lower region of the contact hole CNH.The first contact CT1 may include a first barrier pattern BM1 and afirst conductive pattern FM1. The first barrier pattern BM1 may bebetween the first conductive pattern FM1 and the first or secondsource/drain pattern SD1 and SD2. The first barrier pattern BM1 maycover both side surfaces and a bottom surface of the first conductivepattern FM1. The first barrier pattern BM1 may not cover a top surfaceof the first conductive pattern FM1.

The diffusion barrier layer INH may be on the first contact CT1. In animplementation, the diffusion barrier layer INH may be on the firstconductive pattern FM1 of the first contact CT1, and a top surface ofthe diffusion barrier layer INH may be coplanar with a top surface ofthe first barrier pattern BM1 of the first contact CT1. In animplementation, the top surface of the diffusion barrier layer INH maybe coplanar with the top surface of the first barrier pattern BM1 of thefirst contact CT1 and with a top surface of the first interlayeredinsulating layer 110 (see, e.g., FIG. 16). In an implementation, secondinterlayered insulating layer 120 may overlap with the top surface ofthe first barrier pattern BM1 of the first contact CT1 such that a widthof the first contact CT1 in the first direction D1 or the seconddirection D2 is greater than a width of the second contact CT2 in thefirst direction D1 or the second direction D2.

In an implementation, the top surface of the first conductive patternFM1 may be lower (e.g., closer to the substrate 100 in the thirddirection D3) than the top surface of the first barrier pattern BM1. Arecess region RR may be defined by the top surface of the firstconductive pattern FM1 and an inner side surface BIW of the firstbarrier pattern BM1, and the diffusion barrier layer INH may be formedin the recess region RR. Accordingly, an outer side surface IOW of thediffusion barrier layer INH may be in contact (e.g., direct contact)with the inner side surface BIW of the first barrier pattern BM1.

The second contact CT2 may be in an upper region of the contact holeCNH. The second contact CT2 may include a second barrier pattern BM2 anda second conductive pattern FM2. The second barrier pattern BM2 maycover both side surfaces of the second conductive pattern FM2. In animplementation, the second barrier pattern BM2 may be selectively formedon only both side surfaces of the second conductive pattern FM2, and abottom surface of the second conductive pattern FM2 may be covered(e.g., in contact) with the diffusion barrier layer INH.

The outer side surface IOW of the diffusion barrier layer INH may be incontact with the first barrier pattern BM1, and the top surface of thediffusion barrier layer INH may be in contact with the bottom surface ofthe second conductive pattern FM2. Some of metallic elements in thesecond conductive pattern FM2 may be diffused to a neighboring patternthrough the diffusion barrier layer INH. According to an embodiment, thediffusion barrier layer INH may be in the recess region RR and may besurrounded by the first conductive pattern FM1 and the first barrierpattern BM1. In an implementation, it is possible to effectively preventthe metallic elements in the second conductive pattern FM2 from beingdiffused to the outside of the active contact AC and to help improve thereliability of the semiconductor device.

The first and second barrier patterns BM1 and BM2 may be formed of orinclude a metal nitride (e.g., titanium nitride, tungsten nitride, ortantalum nitride). The first conductive pattern FM1 may be formed of orinclude a metallic material (e.g., aluminum, copper, tungsten,molybdenum, or cobalt). The second conductive pattern FM2 may be formedof or include a metallic material (e.g., aluminum, copper, tungsten,molybdenum, or cobalt). In an implementation, the second conductivepattern FM2 may include a metal material different from that of thefirst conductive pattern FM1. In an implementation, the first conductivepattern FM1 may be formed of or include tungsten, and the secondconductive pattern FM2 may be formed of or include cobalt.

In an implementation, the diffusion barrier layer INH may include, e.g.,acetylacetone or bis(diethylamino) silane. In an implementation, thediffusion barrier layer INH may have a thickness of, e.g., 5 Å to 50 Å(e.g., as measured in the third direction D3).

Referring back to FIG. 2A, the largest width of the first contact CT1 inthe second direction D2 may be a first width W1, and the largest widthof the second contact CT2 in the second direction D2 may be a secondwidth W2. The first width W1 may be greater than the second width W2.The width of the first contact CT1 in the first direction D1 may also begreater than the width of the second contact CT2 in the first directionD1. In an implementation, the largest width of the second contact CT2 inthe second direction D2 may be substantially equal to the largest widthof the diffusion barrier layer INH in the second direction D2.

Referring back to FIGS. 1 and 2A to 2D, a silicide pattern SC may bebetween the active contact AC and the first source/drain pattern SD1 andbetween the active contact AC and the second source/drain pattern SD2.The active contact AC may be electrically connected to the secondsource/drain pattern SD1 or SD2 through the silicide pattern SC. Thesilicide pattern SC may be formed of or include a metal-silicide (e.g.,titanium silicide, tantalum silicide, tungsten silicide, nickelsilicide, or cobalt silicide).

The third interlayered insulating layer 130 may be on the secondinterlayered insulating layer 120. Interconnection lines M1 and firstand second vias V1_a and V1_b may be in the third interlayeredinsulating layer 130. The interconnection line M1 may extend in thesecond direction D2. A cell boundary extending in the second directionD2 may be defined at both ends of the logic cell, and some of theinterconnection lines M1 may be on the cell boundary. Theinterconnection lines M1 may be spaced apart from each other, by aspecific distance, in the first direction D1.

The first and second vias V1_a and V1_b may be below the interconnectionlines M1 (e.g., between the interconnection lines M1 and the substrate100 in the third direction D3). The first vias V1_a may be respectivelybetween the interconnection lines M1 and the active contacts AC toelectrically connect the interconnection lines M1 to the active contactsAC. The second vias V1_b may be respectively between the interconnectionlines M1 and the gate electrodes GE to electrically connect theinterconnection lines M1 to the gate electrodes GE. The interconnectionline M1 and the first or second via V1_a or V1_b may be formed by adamascene process or a dual damascene process.

Referring back to FIG. 2D, the gate electrode GE may face the first topsurface TS1 of the first channel pattern CH1 and at least one of thefirst side surfaces SW1 of the first channel pattern CH1. The gateelectrode GE may face the second top surface TS2 of the second channelpattern CH2 and at least one of the second side surfaces SW2 of thesecond channel pattern CH2. In an implementation, the transistoraccording to the present embodiment may be a three-dimensionalfield-effect transistor (e.g., FinFET), in which the gate electrode GEthree-dimensionally surrounds the channel patterns CH1 and CH2.

FIGS. 3, 5, 7, 9, and 11 are plan views of stages in a method offabricating a semiconductor device, according to an embodiment. FIGS. 4,6A, 8A, 10A, and 12A are sectional views taken along lines A-A′ of FIGS.3, 5, 7, 9, and 11, respectively. FIGS. 6B, 8B, 10B, and 12B aresectional views taken along lines B-B′ of FIGS. 5, 7, 9, and 11,respectively. FIGS. 6C, 8C, 10C, and 12C are sectional views taken alonglines C-C′ of FIGS. 5, 7, 9, and 11, respectively. FIGS. 10D and 12D aresectional views taken along lines D-D′ of FIGS. 9 and 11, respectively.

Referring to FIGS. 3 and 4, the substrate 100 including the first andsecond active regions PR and NR may be provided. The substrate 100 maybe patterned to form the first and second active patterns AP1 and AP2.The first active patterns AP1 may be formed on the first active regionPR, and the second active patterns AP2 may be formed on the secondactive region NR. The first trench TR1 may be formed between the firstactive patterns AP1 and between the second active patterns AP2.

The substrate 100 may be patterned to form the second trench TR2 betweenthe first and second active regions PR and NR. The second trench TR2 maybe formed to be deeper than the first trench TR1 (e.g., as measured inthe third direction D3).

The device isolation layer ST may be formed on the substrate 100 to fillthe first and second trenches TR1 and TR2. The device isolation layer STmay be formed of or include an insulating material (e.g., siliconoxide). The device isolation layer ST may be recessed to expose upperportions of the first and second active patterns AP1 and AP2.Accordingly, the upper portions of the first and second active patternsAP1 and AP2 may protrude vertically above the device isolation layer ST(e.g., in the third direction D3).

Referring to FIGS. 5 and 6A to 6C, sacrificial patterns PP may be formedto cross the first and second active patterns AP1 and AP2. Thesacrificial patterns PP may be line-shaped or bar-shaped patternsextending in the first direction D1. In an implementation, the formationof the sacrificial patterns PP may include forming a sacrificial layeron the substrate 100, forming hard mask patterns MA on the sacrificiallayer, and patterning the sacrificial layer using the hard mask patternsMA as an etch mask. The sacrificial layer may be formed of or includepolysilicon.

A pair of the gate spacers GS may be formed on both side surfaces ofeach of the sacrificial patterns PP. The gate spacers GS may also beformed on both side surfaces of each of the first and second activepatterns AP1 and AP2. A portion of the side surfaces of each of thefirst and second active patterns AP1 and AP2 may not be covered with thedevice isolation layer ST and the sacrificial patterns PP and may be incontact with the gate spacers GS.

The formation of the gate spacers GS may include conformally forming agate spacer layer on the substrate 100 and the anisotropically etchingthe gate spacer layer. The gate spacer layer may be formed of orinclude, e.g., SiCN, SiCON, or SiN. In an implementation, the gatespacer layer may be a multi-layered structure, which includes at leasttwo different materials selected from SiCN, SiCON, and SiN.

Referring to FIGS. 7 and 8A to 8C, recesses RS may be formed in an upperportion of each of the first and second active patterns AP1 and AP2. Apair of the recesses RS may be formed at both sides of each of thesacrificial patterns PP. The formation of the recesses RS may includeetching the upper portions of the first and second active patterns AP1and AP2 using the hard mask patterns MA and the gate spacers GS as anetch mask. During the etching process, the gate spacers GS may beremoved from both side surfaces of each of the first and second activepatterns AP1 and AP2. The exposed portion of the device isolation layerST may be recessed, during the etching process.

A first mask layer MP may be formed to selectively cover the secondactive patterns AP2. The first mask layer MP may be formed toselectively cover the second active region NR and to expose the firstactive region PR. The first mask layer MP may expose the first activepatterns AP1.

The first source/drain patterns SD1 may be formed to fill the recessesRS of the first active patterns AP1 exposed by the first mask layer MP.In an implementation, the formation of the first source/drain patternSD1 may include performing a selective epitaxial growth process usingthe exposed inner surface of the recess RS as a seed layer. The firstsource/drain patterns SD1 may be formed, and the first channel patternCH1 may be defined between each pair of the first source/drain patternsSD1. In an implementation, the selective epitaxial growth process mayinclude a chemical vapor deposition (CVD) process or a molecular beamepitaxy (MBE) process.

The first source/drain pattern SD1 may be formed of or include a secondsemiconductor material whose lattice constant is greater than a latticeconstant of a first semiconductor material of the substrate 100. In animplementation, the first semiconductor material may be silicon (Si),and the second semiconductor material may be germanium (Ge). The firstsource/drain pattern SD1 may be formed of a plurality of stackedsemiconductor layers. The formation of the first source/drain patternSD1 may include sequentially forming the semiconductor layers. In animplementation, the semiconductor layers may constitute a buffer layer,a main layer, and a capping layer.

Referring to FIGS. 9 and 10A to 10D, the first mask layer MP may beremoved. A second mask layer may be formed to selectively cover thefirst active patterns AP1. The second mask layer may selectively coverthe first active region PR and may expose the second active region NR.The second mask layer may expose the second active patterns AP2.

The second source/drain patterns SD2 may be formed to fill the recessesRS of the second active patterns AP2 exposed by the second mask layer.In an implementation, the formation of the second source/drain patternsSD2 may include performing a selective epitaxial growth process usingthe exposed inner surfaces of the recesses RS as a seed layer. Thesecond source/drain patterns SD2 may be formed of or include the samesemiconductor element (e.g., silicon (Si)) as the first semiconductormaterial of the substrate 100. Thereafter, the second mask layer may beremoved.

The first interlayered insulating layer 110 may be formed to cover thefirst and second source/drain patterns SD1 and SD2, the gate spacers GS,and the hard mask patterns MA. In an implementation, the firstinterlayered insulating layer 110 may be formed of or include siliconoxide.

A planarization process may be performed on the first interlayeredinsulating layer 110 to expose the top surfaces of the sacrificialpatterns PP. The planarization of the first interlayered insulatinglayer 110 may be performed using an etch-back process or a chemicalmechanical polishing (CMP) process. In an implementation, the firstinterlayered insulating layer 110 may have a top surface that iscoplanar with the top surfaces of the sacrificial patterns PP and thetop surfaces of the gate spacers GS.

Each of the sacrificial patterns PP may be replaced with the gateelectrode GE and the gate dielectric pattern GI. In an implementation,the exposed sacrificial patterns PP may be selectively removed to forman empty space. The gate dielectric pattern GI may be formed in theempty space (that was formed by removing the sacrificial pattern PP).The gate electrode GE may be formed on the gate dielectric pattern GI tofill the empty space.

The gate dielectric pattern GI may be conformally formed by an atomiclayer deposition (ALD) and/or a chemical oxidation process. In animplementation, the gate dielectric pattern GI may be formed of orinclude a high-k dielectric material. In an implementation, the gatedielectric pattern GI may be formed of or include a ferroelectricmaterial.

The formation of the gate electrode GE may include forming a gateelectrode layer on the gate dielectric pattern GI and planarizing thegate electrode layer. In an implementation, the gate electrode layer mayinclude a first gate electrode layer, which may be formed of or includesa metal nitride, and a second gate electrode layer, which may be formedof or includes a low resistance metal.

An upper portion of the gate electrode GE may be selectively etched torecess the gate electrode GE. The recessed top surface of the gateelectrode GE may be lower than the top surface of the first interlayeredinsulating layer 110 and the top surfaces of the gate spacers GS. Thegate capping pattern GP may be formed on the recessed gate electrode GE.The formation of the gate capping pattern GP may include forming a gatecapping layer to cover the recessed gate electrode GE and planarizingthe gate capping layer to expose the top surface of the firstinterlayered insulating layer 110. In an implementation, the gatecapping layer may be formed of or include, e.g., SiON, SiCN, SiCON, orSiN.

Referring to FIGS. 11 and 12A to 12D, the second interlayered insulatinglayer 120 may be formed on the first interlayered insulating layer 110.The second interlayered insulating layer 120 may be formed of or includesilicon oxide or a low-k oxide material. In an implementation, the low-koxide materials may include carbon-doped silicon oxide (e.g., SiCOH).The second interlayered insulating layer 120 may be formed by a CVDprocess.

The contact holes CNH may be formed to penetrate the second and firstinterlayered insulating layers 120 and 110 and to expose the first andsecond source/drain patterns SD1 and SD2.

The first contact CT1 may be formed to fill a lower region of each ofthe contact holes CNH. The first contact CT1 may be in contact with thefirst or second source/drain pattern SD1 and SD2. The formation of thefirst contact CT1 may include forming the first barrier pattern BM1 andthe first conductive pattern FM1. In an implementation, a first barrierlayer may be formed to fill the contact holes CNH. A first conductivelayer may be formed on the first barrier layer to fill the contact holesCNH. The first barrier pattern BM1 and the first conductive pattern FM1may be formed by performing a planarization process on the first barrierlayer and the first conductive layer. The first barrier layer may beformed of or include a metal nitride, and the first conductive layer maybe formed of or include a metallic material.

Next, an upper portion of the first conductive pattern FM1 may berecessed. The recess region RR may be defined by the top surface of thefirst conductive pattern FM1 and the inner side surface BIW of the firstbarrier pattern BM1, and the diffusion barrier layer INH may be formedon the recess region RR.

Referring back to FIGS. 1 and 2A to 2D, the second contact CT2 may beformed on the diffusion barrier layer INH to fill the upper region ofthe contact hole CNH. The formation of the second contact CT2 mayinclude forming the second barrier pattern BM2 and the second conductivepattern FM2. In an implementation, a second barrier layer may be formedon the top surface of the diffusion barrier layer INH, and a secondconductive layer may be formed on the second barrier layer. Aplanarization process may be performed on the second barrier layer andthe second conductive layer to expose the top surface of the secondinterlayered insulating layer 120, and thus, the second barrier patternBM2 and the second conductive pattern FM2 may be formed. The secondbarrier pattern BM2 may be formed to surround a side surface of thesecond conductive pattern FM2. The second barrier pattern BM2 and thesecond conductive pattern FM2 may have bottom surfaces that are incontact with the top surface of the diffusion barrier layer INH.

FIGS. 13 and 14 are sectional views of an active contact according to anembodiment and in detail illustrating a region ‘M’ of FIG. 2A and aportion ‘N’ of FIG. 2C. In the following description, an elementpreviously described with reference to FIGS. 1 and 2A to 2D may beidentified by the same reference number without repeating an overlappingdescription thereof, for the sake of brevity.

In an implementation, referring to FIG. 13, the diffusion barrier layerINH may have a rounded bottom surface. To realize such a shape of thediffusion barrier layer INH, an etching process may be performed torecess an exposed top surface of the first conductive pattern FM1. In animplementation, the shape of the top surface of the first conductivepattern FM1 may vary depending on the method of the etching process, andthis means that by adjusting the etching process on the first conductivepattern FM1, the top surface of the first conductive pattern FM1 mayhave a rounded (e.g., concave) shape. Thus, the diffusion barrier layerINH on the first conductive pattern FM1 may be formed to have therounded bottom (e.g., convex) surface.

Referring to FIG. 14, the diffusion barrier layer INH may have a topsurface that is lower (e.g., closer to the substrate 100 in the thirddirection D3) than a top surface of the first barrier pattern BM1.Accordingly, the second barrier pattern BM2 and the second conductivepattern FM2 may have bottom surfaces that are lower than the top surfaceof the first barrier pattern BM1. An inner side surface of the firstbarrier pattern BM1 may be in contact with an outer side surface of thesecond barrier pattern BM2.

FIGS. 15A to 15D are sectional views, which are respectively taken alonglines A-A′, B-B′, C-C′, and D-D′ of FIG. 1. In the followingdescription, an element previously described with reference to FIGS. 1and 2A to 2D may be identified by the same reference number withoutrepeating an overlapping description thereof, for the sake of brevity.

Referring to FIGS. 1 and 15A to 15D, the substrate 100 including thefirst and second active regions PR and NR may be provided. The deviceisolation layer ST may be provided on the substrate 100. The deviceisolation layer ST may define the first active pattern AP1 and thesecond active pattern AP2 in an upper portion of the substrate 100. Thefirst active pattern AP1 and the second active pattern AP2 may bedefined on the first active region PR and the second active region NR,respectively.

The first active pattern AP1 may include the first channel patterns CH1,which are vertically stacked. The stacked first channel patterns CH1 maybe spaced apart from each other in the third direction D3. The stackedfirst channel patterns CH1 may be overlapped with each other, whenviewed in a plan view (e.g., along the third direction D3). The secondactive pattern AP2 may include the second channel patterns CH2, whichare vertically stacked. The stacked second channel patterns CH2 may bespaced apart from each other in the third direction D3. The stackedsecond channel patterns CH2 may be overlapped with each other, whenviewed in a plan view. The first and second channel patterns CH1 and CH2may be formed of or include, e.g., silicon (Si), germanium (Ge), orsilicon-germanium (SiGe).

The first active pattern AP1 may further include the first source/drainpatterns SD1. The second channel patterns CH2 may be stacked betweeneach adjacent pair of the first source/drain patterns SD1. The stackedfirst channel patterns CH1 may connect an adjacent pair of the firstsource/drain patterns SD1 to each other.

The second active pattern AP2 may further include the secondsource/drain patterns SD2. The second channel patterns CH2 may bestacked between each adjacent pair of the second source/drain patternsSD2. The stacked second channel patterns CH2 may connect an adjacentpair of the second source/drain patterns SD2 to each other.

The gate electrodes GE may cross the first and second channel patternsCH1 and CH2 and extend in the first direction D1. The gate electrode GEmay be overlapped with the first and second channel patterns CH1 andCH2, when viewed in a plan view. A pair of the gate spacers GS may be onboth side surfaces of the gate electrode GE. The gate capping pattern GPmay be on the gate electrode GE.

The gate electrode GE may surround each of the first and second channelpatterns CH1 and CH2 (e.g., see FIG. 15D). The gate electrode GE may beon the first top surface TS1, at least one first side surface SW1, and afirst bottom surface BS1 of the first channel pattern CH1. The gateelectrode GE may be on the second top surface TS2, at least one secondside surface SW2, and a second bottom surface BS2 of the second channelpattern CH2. In an implementation, the gate electrode GE may enclosetop, bottom, and both side surfaces of each of the first and secondchannel patterns CH1 and CH2. A transistor according to the presentembodiment may be a three-dimensional field-effect transistor (e.g., amulti-bridge channel field-effect transistor (MBCFET)), in which thegate electrode GE three-dimensionally surrounds the channel patterns CH1and CH2.

The gate dielectric pattern GI may be between each of the first andsecond channel patterns CH1 and CH2 and the gate electrode GE. The gatedielectric pattern GI may surround each of the first and second channelpatterns CH1 and CH2.

On the second active region NR, an insulating pattern IP may be betweenthe gate dielectric pattern GI and the second source/drain pattern SD2(e.g., in the second direction D2). The gate electrode GE may be spacedapart from the second source/drain pattern SD2 by the gate dielectricpattern GI and the insulating pattern IP. In an implementation, theinsulating pattern IP may not be provided on the first active region PR.

The first interlayered insulating layer 110 and the second interlayeredinsulating layer 120 may be on the substrate 100. The active contacts ACmay penetrate the first and second interlayered insulating layers 110and 120 and may be connected to the first and second source/drainpatterns SD1 and SD2, respectively. Each of the active contacts AC mayinclude the first contact CT1, the diffusion barrier layer INH on thefirst contact CT1, and the second contact CT2 on the diffusion barrierlayer INH. The first and second contacts CT1 and CT2 and the diffusionbarrier layer INH may be configured to have substantially the samefeatures as those described with reference to FIGS. 2A to 2D.

FIG. 16 illustrates a section view of a semiconductor device accordingto an embodiment.

Referring to FIG. 16, a lower region of each of the contact holes CNHmay be formed to penetrate the first interlayered insulating layer 110and to expose the first and second source/drain patterns SD1 and SD2.

The first contact CT1 may be formed to fill the lower region of each ofthe contact holes CNH. The first contact CT1 may be in contact with thefirst or second source/drain pattern SD1 and SD2. The formation of thefirst contact CT1 may include forming the first barrier pattern BM1 andthe first conductive pattern FM1. In an implementation, a first barrierlayer may be formed to fill the lower region of each of the contactholes CNH. A first conductive layer may be formed on the first barrierlayer to fill the lower region of each of the contact holes CNH. Thefirst barrier pattern BM1 and the first conductive pattern FM1 may beformed by performing a planarization process on the first barrier layerand the first conductive layer to expose the top surface of the firstinterlayered insulating layer 110. The first barrier layer may be formedof or include a metal nitride, and the first conductive layer may beformed of or include a metallic material.

Next, the second interlayered insulating layer 120 may be formed on thefirst interlayered insulating layer 110. The second interlayeredinsulating layer 120 may expose the top surface of the first conductivepattern FM1, and may not expose the top surface of the first barrierpattern BM1. In other words, the second interlayered insulating layer120 may cover a top surface of the gate capping pattern GP, top surfacesof the gate spacers, and the top surface of the first barrier patternBM1.

Next, an upper portion of the first conductive pattern FM1 may berecessed. The recess region RR may be defined by the top surface of thefirst conductive pattern FM1 and the inner side surface BIW of the firstbarrier pattern BM1, and the diffusion barrier layer INH may be formedon the recess region RR.

Next, the second contact CT2 may be formed on the diffusion barrierlayer INH to fill an upper region of each of the contact holes CNH. Inan implementation, a width of the upper region of each of the contactholes CNH in the first direction D1 or the second direction D2 issmaller than a width of the lower region of each of the contact holesCNH in the first direction D1 or the second direction D2. The formationof the second contact CT2 may include forming the second barrier patternBM2 and the second conductive pattern FM2. In an implementation, asecond barrier layer may be formed on the top surface of the diffusionbarrier layer INH, and a second conductive layer may be formed on thesecond barrier layer. A planarization process may be performed on thesecond barrier layer and the second conductive layer to expose the topsurface of the second interlayered insulating layer 120, and thus, thesecond barrier pattern BM2 and the second conductive pattern FM2 may beformed. The second barrier pattern BM2 may be formed to surround a sidesurface of the second conductive pattern FM2. The second barrier patternBM2 and the second conductive pattern FM2 may have bottom surfaces thatare in contact with the top surface of the diffusion barrier layer INH.

In an implementation, the top surface of the diffusion barrier layer INHmay be coplanar with the top surface of the first barrier pattern BM1 ofthe first contact CT1 and with a top surface of the first interlayeredinsulating layer 110. Also, a bottom surface of the second conductivepattern FM2 and a bottom surface of the second barrier pattern BM2 maybe coplanar with the top surface of the first interlayered insulatinglayer 110.

According to an embodiment, an active contact of a semiconductor devicemay be formed to have a dual contact structure including first andsecond contacts, and a diffusion barrier layer therebetween. In thiscase, it is possible to improve the reliability of the semiconductordevice. In addition, the diffusion barrier layer may help prevent ametallic element in the active contact from being diffused intoneighboring patterns and may help prevent performance of thesemiconductor device from being deteriorated.

One or more embodiments may provide a semiconductor device including afield effect transistor.

One or more embodiments may provide a semiconductor device with improvedelectrical characteristics.

Example embodiments have been disclosed herein, and although specificterms are employed, they are used and are to be interpreted in a genericand descriptive sense only and not for purpose of limitation. In someinstances, as would be apparent to one of ordinary skill in the art asof the filing of the present application, features, characteristics,and/or elements described in connection with a particular embodiment maybe used singly or in combination with features, characteristics, and/orelements described in connection with other embodiments unless otherwisespecifically indicated. Accordingly, it will be understood by those ofskill in the art that various changes in form and details may be madewithout departing from the spirit and scope of the present invention asset forth in the following claims.

What is claimed is:
 1. A semiconductor device, comprising: a substrateincluding an active pattern; a gate electrode crossing the activepattern and extending in a first direction; a source/drain pattern onthe active pattern and adjacent to a side of the gate electrode; and anactive contact in a contact hole on the source/drain pattern, wherein:the active contact includes: a first contact in a lower region of thecontact hole, the first contact including a first barrier pattern and afirst conductive pattern; a diffusion barrier layer on the firstconductive pattern of the first contact; and a second contact on thediffusion barrier layer, the second contact including a second barrierpattern and a second conductive pattern, a top surface of the diffusionbarrier layer is coplanar with a top surface of the first barrierpattern of the first contact, and the second conductive pattern of thesecond contact is in direct contact with the top surface of thediffusion barrier layer.
 2. The device as claimed in claim 1, wherein alargest width of the first contact in a second direction crossing thefirst direction is larger than a largest width of the second contact inthe second direction.
 3. The device as claimed in claim 1, wherein alargest width of the second contact in a second direction crossing thefirst direction is equal to a largest width of the diffusion barrierlayer in the second direction.
 4. The device as claimed in claim 1,wherein a thickness of the diffusion barrier layer ranges from 5 Å to 50Å.
 5. The device as claimed in claim 1, wherein the diffusion barrierlayer includes acetylacetone or bis(diethylamino) silane.
 6. The deviceas claimed in claim 1, wherein the diffusion barrier layer has a roundedbottom surface.
 7. The device as claimed in claim 1, further comprising:an interconnection line electrically connected to the active contact;and a via between the active contact and the interconnection line tovertically connect the active contact to the interconnection line. 8.The device as claimed in claim 1, further comprising a device isolationlayer covering the active pattern, wherein the active pattern includesan upper portion that vertically protrudes above the device isolationlayer.
 9. The device as claimed in claim 1, wherein: the active patternincludes vertically stacked channel patterns, and the gate electrode ison a top surface, a bottom surface, and both side surfaces of each ofthe channel patterns.
 10. A semiconductor device, comprising: asubstrate including an active pattern; a gate electrode crossing theactive pattern and extending in a first direction; a source/drainpattern on the active pattern and adjacent to a side of the gateelectrode; and an active contact in a contact hole on the source/drainpattern, wherein: the active contact includes: a first contact in alower region of the contact hole, the first contact including a firstbarrier pattern and a first conductive pattern; a diffusion barrierlayer on the first conductive pattern of the first contact; and a secondcontact on the diffusion barrier layer, the second contact including asecond barrier pattern and a second conductive pattern, an outer sidesurface of the diffusion barrier layer is in contact with an inner sidesurface of the first barrier pattern of the first contact, and thesecond conductive pattern of the second contact is in direct contactwith a top surface of the diffusion barrier layer.
 11. The device asclaimed in claim 10, wherein a largest width of the first contact in asecond direction crossing the first direction is larger than a largestwidth of the second contact in the second direction.
 12. The device asclaimed in claim 10, wherein a largest width of the second contact in asecond direction crossing the first direction is equal to a largestwidth of the diffusion barrier layer in the second direction.
 13. Thedevice as claimed in claim 10, wherein a thickness of the diffusionbarrier layer ranges from 5 Å to 50 Å.
 14. The device as claimed inclaim 10, wherein the diffusion barrier layer includes acetylacetone orbis(diethylamino) silane.
 15. The device as claimed in claim 10, whereinthe top surface of the diffusion barrier layer is lower than a topsurface of the first barrier pattern of the first contact.
 16. Asemiconductor device, comprising: a substrate including a first activeregion and a second active region, which are spaced apart from eachother in a first direction; a first active pattern on the first activeregion and a second active pattern on the second active region, thefirst active pattern and the second active pattern extending in a seconddirection crossing the first direction; a first source/drain pattern onan upper portion of the first active pattern and a second source/drainpattern on an upper portion of the second active pattern; gateelectrodes crossing the first active pattern and the second activepattern and extending in the first direction, the gate electrodes beingarranged in the second direction; an interlayered insulating layercovering the first source/drain pattern, the second source/drainpattern, and the gate electrodes; and an active contact in a contacthole on one of the first source/drain pattern and the secondsource/drain pattern, wherein: the active contact includes: a firstcontact in a lower region of the contact hole, the first contactincluding a first barrier pattern and a first conductive pattern; adiffusion barrier layer on the first conductive pattern of the firstcontact; and a second contact on the diffusion barrier layer, the secondcontact including a second barrier pattern and a second conductivepattern, a top surface of the first conductive pattern is recessed, suchthat a recess region is defined at an upper portion of the first contactby the top surface of the first conductive pattern and an inner sidesurface of the first barrier pattern, the diffusion barrier layer is inthe recess region, and the second conductive pattern of the secondcontact is in direct contact with a top surface of the diffusion barrierlayer.
 17. The device as claimed in claim 16, wherein a largest width ofthe first contact in the second direction is greater than a largestwidth of the second contact in the second direction.
 18. The device asclaimed in claim 16, wherein a largest width of the second contact inthe second direction is equal to a largest width of the diffusionbarrier layer in the second direction.
 19. The device as claimed inclaim 16, wherein a thickness of the diffusion barrier layer ranges from5 Å to 50 Å.
 20. The device as claimed in claim 16, wherein thediffusion barrier layer includes acetylacetone or bis(diethylamino)silane.